A beetle in colour under a low powered microscope. This may as well be a painting, a pointillist painting, or rather a 'post-pointillist' painting. To be post-pointillistic, I would recommend moving beyond the dyes and pigments of Seurat and Signac - on to a new use of light compared with conventional pointillism. A dot painting made of photonic crystals can make colour without normal dyes or pigments. A pointillist painting with no dyes or pigments? That equals post-pointillism to some extent surely? Christian Mille and I are studying these. Specimen NHM, Stockholm.

Green glass shard that fell as volcanic ash on Sweden 15th-16th April from the eruption of Eyjafjallajökull. Scale is 25 microns. This particle was removed from a larger, 1mm ash particle and viewed with a Zeiss microscope without using crossed polarizers, like in the last post. The colour in this photo is entirely due to the presence of iron and other metals in the glass.

Mineral ash from the Eyjafjallajökull volcano. This crystalline shard of mineral dust fell on Sweden on 15th-16th April 2010 as seen through a Zeiss polarizing microscope. The colour is due to birefringence typical of crystals rather than glass. This particle was removed from a larger ash particle about 1mm in size. The same particle was "glued" together with much smaller particles and was accompanied by particles of glass. A dense cloud of 1mm particles each made of shards like this can do serious damage to a jet engine. The graduated scale shown is 50 microns.